1. Field
The following description relates to a light emitting diode (LED) driving technology. The following description also relates to an LED driving circuit and lighting apparatus using such a technology for performing an adjustment of an LED brightness level and a removal of an LED flicker through a Triode for Alternating Current (TRIAC) dimmer.
2. Description of Related Art
An LED (light emitting diode) lighting apparatus is an environmental-friendly light source of a lighting system that has an advantage in that it is able to endure a pressure and/or a vibration. The LED lighting apparatus also has the properties that it is easy to regulate a brightness of an LED and an LED has a high speed response. Furthermore, because the brightness of the LED lighting apparatus is easily regulated, a quantity of consumed electricity in standby state may be reduced by reducing the LED's brightness and the LED lighting apparatus may thus be able to save energy. Hence, the LED lighting apparatus may decrease a power consumption compared with an alternative lighting source to replace the alternative lighting apparatus. An example LED lighting apparatus may use an AC-type direct driving circuit to directly use an alternating current in lieu of direct current.
In the case of the alternative lighting apparatus, switching of a power switch controls operation of the lighting apparatus. A dimming level of a next section is potentially determined based on a dimming level of a previous section or based on a turn-on time of the power switch. In other words, the alternative LED lighting apparatus requires the power switch be provided separately for driving of an LED.
However, an AC direct-coupled method is potentially preferred because it offers advantages of lightness and small size so as to be preferred to a DC power method. As a range of use of such an AC direct-coupled lighting apparatus becomes wider, a flicker and decline of lamp efficiency may occur during operation of such an apparatus. The flicker may arise as a result of a situation in which turn-on driving points are different from each other. Thus, a time difference in light emission may lead the LED to flicker. Such flickering may cause an LED user to feel tired. For improved management of the flicker, a capacitive element having a large capacity is used. However, use of such a capacitive element leads to the occurrence of a problem of a decrease of a power-factor.